Field of the Invention
The present invention relates to a drain bolt coupled to an oil tank of a vehicle or the like. More particularly, the present invention relates to a drain bolt configured to be forcibly withdrawn from an oil tank. The drain bolt has an elastic screw section coupled to a distal end of a fastening screw section, wherein the elastic screw section is formed of a soft material and has a color distinguishable from that of the fastening screw section, and threads of the fastening screw section and threads of the elastic screw section are formed to be continuous to each other to maintain the sealing ability of the drain bolt, whereby the drain bolt can be rapidly separated from an oil tank by unfastening the fastening screw section from the oil tank and then forcibly pulling the elastic screw section from the oil tank.
Description of the Related Art
In general, when surfaces of two metal members are rubbed against each other, frictional heat is generated. Frictional heat is a friction-induced loss of energy. In the case of a vehicle engine, friction reduces the output power of the engine and wears the engine, such that sintering occurs when heated to a high temperature.
Thus, in an engine generating power through relative movement of metal members, cooling and lubrication using engine oil is intended to remove sources of frictional heat and wear from the two metal surfaces that are rubbed against each other within the engine, thereby allowing the engine to smoothly operate and improving the endurance of the engine.
However, engine oil having such a use is subjected to degradation while being repeatedly circulated. The lubrication function of engine oil degrades as impurities are mixed with engine oil. Engine oil must be replaced with new oil after being used for a certain period of time in order to increase the longevity of an engine and improve the efficiency of the engine. Waste engine oil that has reached its lifespan is discharged from an oil tank in which engine oil is contained by separating a drain bolt fastened to a bottom outlet of the oil tank.
A conventional drain bolt is typically in the shape of a metal bolt. The drain bolt must be completely separated from the bottom outlet so that engine oil is discharged completely. However, it is difficult for a mechanic to visually recognize a precise point in time that the drain bolt is completely separated from the outlet and the mechanic must be positioned directly below the drain bolt to separate the drain bolt from the outlet. Thus, there is a danger that the mechanic's face or hand may be burned by hot waste oil pouring out at the moment that the drain bolt is separated.
Since a small amount of waste oil is discharged from the oil tank when the drain bolt is slightly separated from the outlet without being completely separated therefrom, even a skillful mechanic cannot avoid his or her hands or clothes coming into contact with waste engine oil. Further, it is highly possible that the drain bolt separated from the outlet may drop into a waste oil collecting tank and is contaminated by waste oil or lost, thereby making an oil exchange operation to be complicated. In addition, a portion of iron filings mixed with waste engine oil is not discharged from the oil tank and accumulates around the outlet in the bottom of an oil pan, thereby contaminating newly-supplied engine oil, which is problematic.
The information disclosed in the Background of the Invention section is only for the enhancement of understanding of the background of the invention, and should not be taken as an acknowledgment or as any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art.